Blood in Breast Milk

Occasionally a mother may notice that her expressed breast milk, or her baby’s regurgitated breast milk after a feed, is streaked or tinged with red, pink or rusty brown suggesting the presence of blood. Is this blood from a cracked nipple or from deeper within the breast? Could the blood be from the baby? Is blood from the breast harmful for a baby to drink? This article looks at common causes of blood in breast milk and answers frequently asked questions.

Signs of blood in breast milk

Breast milk and colostrum can come in a variety of different colours including blue, green, brownish, yellow, gold and clear.1 Small amounts of blood will often go unnoticed unless a mother is expressing her milk or her baby spits up noticeably blood stained milk. Blood in breast milk may colour breast milk bright red, pink, black, olive green or a chocolate brown colour.2 If substantial amounts of blood are swallowed and digested there may be black flecks of blood in the baby’s poop, or the poop may even be black and tarry.3 In the case of blood stained regurgitated milk or blood in stools; contacting your baby’s doctor will help confirm whether the blood is from mother or baby (see below).

What can cause blood in breast milk?

A little blood in breast milk in the early days of breastfeeding is quite common due to the changes within the breast as milk production begins.45  According to Mitchell et al, a temporary bloody nipple discharge may also be seen in up to 24% of women at any time during the course of lactation (Mitchell et al, 2019).

Persistent bleeding. Although not usually serious, any persistent blood from the nipple beyond the first few days after birth should be reported to your health care provider with a view to further investigation (Mitchell et al, 2019). Authors Wilson-Clay and Hoover mention a copious, spontaneous nipple discharge (clear or bloody, and usually one-sided) is one of several possible warning signs of breast cancer.6

Common causes of blood in breast milk

  • “Rusty pipe syndrome” when ducts and milk making cells grow and stretch after birth
  • A cracked or damaged nipple that bleeds as baby sucks
  • Damaged capillaries in the breast due to engorgement or rough handling
  • Intraductal pailloma; a small benign growth on the milk duct lining which bleeds
  • Fibrocystic changes (lumpy breasts)

Rusty pipe syndrome

Rusty pipe syndrome is the name given to small amounts of rusty coloured blood seen in breast milk during the first week or so after birth. It’s thought to be due to extra blood flow to the breast and fast development of glandular tissue causing a little blood to escape into the milk.  It is discussed in Dr Jack Newman’s Guide to Breastfeeding:

It is not surprising that sometimes blood vessels leak a little blood into a duct, and it then comes out of the nipple. It is not dangerous for the mother or the baby. Sometimes when a baby swallows blood he may spit it up because it irritates his stomach, but it really does him no harm. The bleeding usually disappears by 7 to 10 days after birth. Breastfeeding must not be interrupted.

If bleeding carries on after baby is a week old or if bleeding happens at a later stage than the first week, continue breastfeeding but always check with your doctor (Newman, 2014).

Cracked or damaged nipples

If the cause of blood in breast milk is due to a mother’s cracked or damaged nipples, it is important to find the cause of the damage so that this can be addressed and nipples can heal. The most frequent reason for cracked and bleeding nipples is when a baby is attached mostly to the nipple during a feed instead of having a big mouthful of breast tissue as well as the nipple. See our articles on Why does breastfeeding hurt? and Causes of sore nipples or contact your IBCLC lactation consultant for help with positioning and latching your baby.

Damaged capillaries

Breast damage from rough handling such as pressing too hard during hand expression or massage or using a pump with a very high vacuum could cause bleeding from broken capillaries (tiny blood vessels) as they are very delicate.

Intraductal papilloma

Breastfeeding authors Wambach and Spencer7 say that bright-red bleeding from the breast without the presence of sore nipples could indicate an intraductal papilloma. An intraductal papilloma is a small growth in the lining of a duct near the nipple. It is usually noncancerous and doesn’t cause pain8 but can bleed into the duct when disturbed by breastfeeding or pumping and it is a common reason for blood in breast milk 9. Walker explains that if the baby tolerates the blood they can continue breastfeeding but if the baby keeps spitting up, because the blood is making them sick, the mother may have to pump the affected breast until it is clear of blood which usually takes 3-7 days. Bleeding often stops of its own accord without any treatment (Wambach and Spencer, 2021 p 302).

Fibrocystic changes

Fibrocystic breasts is the name used for a group of symptoms in the glandular breast tissue including breast pain, solid lumps and cysts. Breastfeeding A Guide for the Health Profession discusses that fibrocystic breasts are a cause of a discharge of blood from the nipple in pregnancy and lactation in approximately a third of cases but it is not a contraindication to breastfeeding. The authors mention one case where fibrocystic breasts were found to be the cause of an infant vomiting due to the volume of blood in breast milk (Lawrence and Lawrence, 2016).

Frequently asked questions

Can I feed my baby breast milk that has blood in it?

Wambach and Spencer state that a baby will not be harmed by drinking small amounts of blood but consuming larger amounts may cause them to regurgitate the blood (Wambach and Spencer, 2021, p 303). Jack Newman, Canadian paediatrician and breastfeeding expert explains:

Taking the baby off the breast is often suggested if the mother’s nipples bleed from a crack or abrasion. But blood in the milk is not a reason to take the baby off the breast. The issue is the pain the mother feels, not the blood. Blood in the baby’s stomach can cause spitting up but is not dangerous. If we can make the mother’s pain tolerable, even if the nipples continue to bleed, let’s keep the baby on the breast. If the damage is minimized by fixing the way the baby takes the breast, the abrasions/cracks will heal and the bleeding will stop.

Check with a doctor

If your baby has drunk a lot of blood stained breast milk they may have very dark coloured poop in addition to spitting up blood-stained milk. The Australian Breastfeeding Association recommend checking with your doctor;

Occasionally a baby may pass dark bowel motions or may spit up blood-stained milk. This is usually a result of the baby drinking blood-stained breastmilk rather than the blood coming from the baby. It often looks like a lot of blood because the blood can form one large lump in the stomach, which the baby spits up. Swallowed blood will not harm the baby, but tends to irritate the stomach and makes vomiting more likely. However, it is always worthwhile seeking immediate medical advice in these situations.

Could the blood be from my baby?

Your health professionals will be able to determine whether the blood is from baby or the breast by checking the regurgitated blood for foetal or adult haemoglobin 10. The hemoccult test identifies adult haemoglobin and can rule out infant gastrointestinal haemorrhage (Wilson-Clay and Hoover, 2017, p 36).

Other causes of pink breast milk

Food pigments may colour breast milk

Sometimes a food in mother’s diet may colour her breast milk pink e.g. beetroot. In Baby Poop: What Your Pediatrician May Not Tell You author Linda Palmer says that the pigments from natural foods such as beets are usually good antioxidants and don’t need to be avoided. She adds that if if the pigment has coloured the milk this means it has passed through mother’s system undigested and will probably go through baby’s system the same way.

Bacteria can colour milk pink

Thomas Hale describes another possible cause of pink/red milk that may not be blood is a bacteria called Serratia marsescens. Although S. marsescens is normally harmless and commonly found in children’s gastrointestinal tracts it can be the cause of infection, especially for premature babies.

It is unlikely that a baby feeding directly from the mother’s breast will consume enough bacteria to cause disease. However improper handling of breast milk may allow the bacteria to multiply to numbers capable of producing disease. Refrigeration of breast milk and breastfeeding equipment is usually sufficient to prevent Serratia from multiplying and generating pigment.

The author advises never feeding a baby pink-red discoloured breast milk until cleared by a doctor. See the full article for further information.

Expressed breast milk and pump


A little blood in breast milk is not harmful to your breastfed baby and is a common occurrence in the first week or so after a baby’s birth. Reasons for short periods of blood in breast milk include rusty pipe syndrome, cracked bleeding nipples, broken capillaries in the breast or an intraductal papilloma. Any blood in breast milk that continues past the first week after birth, or blood in breast milk that arrives later during lactation should be discussed with your doctor but in most cases breastfeeding can continue.